A common problem among sufferers of back pain is a prolapsed lumbar intervertebral disc, wherein a portion of the disc between two vertebrae in the lower back prolapses outward and causes pressure on a nerve. One method of treatment is by major surgery. Because of the substantial trauma caused by such surgery, it is common for the patient to experience a recovery period of ten to twelve weeks.
Recently a new technique has been developed wherein nucleus material of the prolapsed disc is excised by percutaneous aspiration. The disc nucleus is soft and jelly-like in consistency, and can be resected and aspirated by use of a specially designed cannula. The aspiration cannula is inserted into the nucleus of the prolapsed disc with the aid of a trocar probe, prior to connection of the cannula to an aspirating machine. A major concern is precise placement of the probe to avoid nerve damage.
Since herniation of a disc most frequently occurs between the fourth and fifth lumbar vertebrae, or between the fifth lumbar and sacral vertebrae, the insertion of the probe is very difficult. Particularly in the latter case, the probe must be inserted not only at an angle to the vertical, but also at an angle relative to the sagittal axis, in order to avoid the protective iliac crest of the sacrum. Preferably the probe is inserted at about eight centimeters away from the midline, on the coronal plane of the prolapsed disc level, at an angle of about 45 degrees. In the past, the probe has been inserted by trial and error, while monitoring its placement by fluoroscopic examination.
Devices and means for stereotactic positioning and guiding of a medical probe to a herniated lumbar disc are described in U.S. Pat. Nos. 3,964,480; 4,638,799; 4,750,487; 5,047,036; and 5,080,662. The systems mainly have in common a stereotactic bridge or mounting structure which is attached to an operating or C.T. scan type table. Such structures are mechanically complex, and have limited range of mobility.
There remains a need for new and improved devices to overcome the various difficulties associated with automated percutaneous lumbar discectomy procedures.
Accordingly, it is an object of this invention to provide a self-contained medical probe guidance device which can be hand-manipulated on the contour surface of a human body.
It is another object of this invention to provide a mobile stereotactic device for fluoroscope-monitored alignment and placement of a medical probe for percutaneous lumbar discectomy in a human body.
Other objects and advantages of the present invention shall become apparent from the accompanying description and drawings.